chitown40

Hi guys and girls. Long-time mud member, very recent Club Lexus member, and recent GX owner. I currently own a 2009 GX470 Sport w/ KDSS.

I originally posted this thread on IH8MUD.com, but after reading through it, I thought it might be beneficial for some non-mud members on here as well.

Like some of you guys, I've had the whole gamut of Land Cruisers starting with a 40 series, several 60 series, an 80, and a hundy. Before the GX, I had a 2006 4Runner V6 for a few years, so I'm pretty familiar with the 120 platform. What I'm still learning is the little extras that Lexus slaps on their trucks.

Anyway, I digress. I've been doing a lot of PM on the truck since I got it t the end of 2015. Everything is like new, with the most extensive maintenance being replacement of the power steering fluid with ATF and removal of the front skid plate - basically cleaning up the bolts with a wire wheel and applying anti-seize, basically SOP here in the midwest.

So, yesterday the KDSS light illuminated on the dash. It was during normal driving on my way home from work. The truck sat outside overnight while I was working, with a mild drop in temperature throughout the night. The truck continued to sit level, the ride quality was relatively unchanged, and no other noted changes.

I came home, got on all the forums to read about KDSS with the general theme being a very expensive repair if any components needed replacing. The costs varied from about $1500-$4000. So, next stop was pulling out the Techstream software and plugging in to the truck. There is some good data feeds on the system pressures and operation of the components, and of course the DTCs.

I pulled one code, C1832, which was the Accumulator solenoid (Downside). I'm still familiarizing myself with all the components, but I think this solenoid is for the rear. Techstream provides for two tests, basically cycling the solenoids OPEN/CLOSE. The first test, for the Accumulator solenoid (Upside), properly cycling the solenoid open with a nice audible "CLICK". I performed this test a few times to try and find the exact location of the solenoid. I was working solo, so I ran out of reach to the computer while under the vehicle.

Test #2 was the Accumulator solenoid (Downside). Unfortunately, I did not get the audible "CLICK" when trying to cycle the solenoid. So, either the solenoid went bad, or it was sticking. I had the truck in the garage now, so it was warming up from it's normal place outside in the cold. I let it sit for a few hours, and continued to try and cycle the solenoid with the TS software. Eventually I started hearing the solenoid cycle with the audible "CLICK". I continued to cycle the solenoid with the test until my OCD was satisfied.

Next, I reset the DTC code and drove the truck for a good medium-duration trip. No more light and I appear to have proper operation of the KDSS system again.

Anyway, we'll have to see long-term if the sticking solenoid becomes an intermittent or long-term problem, but so far so good.

So my next question is, what are all your thoughts on KDSS system maintenance? I know this is dealer only deal, and I really hate going to the dealer for any service unless absolutely no other alternative is available, but you need a special high-pressure oil pump to replace the oil in the system. I heard replacement of the AHC hydraulic fluid at 60k intervals from what I've read, but I can't find it written down anywhere. I suppose the fluid replacement service will be mostly labor charges with a small hit for the fluid, so I'm more at ease doing the required maintenance if there is a perceived benefit to the system.

chiph9

Since you had a sticking solenoid, I'd start thinking about a fluid change to maybe flush out any crud that has built-up in there. Sorry, I don't have KDSS so I can't contribute to the conversation about price, etc.

Chip H.

co4wheel

Fluid Flush for sure. I read about it on the net someplace a year ago. I thought you could do it yourself. But its a obvious thing to do as it's basically brake fluid.

chitown40

Thanks guys for the replies.

I've been doing a lot of digging and reading on this, and while I'd like to replace the hydraulic fluid in the KDSS, everything I'm seeing says it's lifetime fluid and sealed unless you have a leak and need to have the system bled and refilled.

Been a few days now and everything is still working nicely, ride quality is good, and no leaks still.

co4wheel

It may be a "Lifetime Fluid" but anything that wears in the system is going to stay in that closed system for a lifetime as well. So while the fluid may be fine the particles floating around in it could cause things to stick or wear faster. Thats the entire point of flushing out the system. Get rid of anything that could cause the sticking or further wear.

chitown40

I get you. I'll have to price this one out, as it seems to be a luxury service item as not every shop or even dealer has the high-pressure oil pump to do the job.

artinist

Anyone have additional information about the flush or an update on the above?

I read someplace that someone took it in to the dealer for a flush and it was about $550 and not every dealer has the high pressure pump to do this job.

mann777

You dont need to do all those test. Just do a zero point calibration . It will clear the ecu and the lite on the cluster. The issue is when there is a abnormality within the Accumulator pressor sensor which has closed due to maybe a lateral acceleration rate and the steering speed angle. The ecm detect and closes the valve and the ecm sends the signal to the cluster. Just do zero point calibration. And you are good to go. Just ensure you should do the test on a absoltely flat ground.

GreggyG

wha262

Ok thanks but could you dumb that down a bit for us non technicians please? My light is on as well. Thx

chiph9

You can search on Youtube for "Lexus Zero Point Calibration" and get a few really badly made videos that should help.

Basically, you're calibrating the yaw rate sensor so that the vehicle knows when it's skidding (and not).
Technically, this should be done after an alignment, since the thrust angle was probably changed.

Chip H.

KrisE

If your KDSS dash light came on and you think your solenoid may be stuck, perhaps this might help:
Situation- no previous KDSS issues. Weather: WET and drastic weather change from 50F to 18F in 6hrs with 50+MPH winds.
Thick ice build up on a curve made the road un-level and banked against the curve, making a demand on the KDSS. Slow speed and still slid slightly. Negotiated out of curve ok, then KDSS warning light came on.
I suspected the solenoid was stuck after reading here. Decided to repeat the situation so as to make an electronic demand on the system (solenoid) to see if it would unstuck itself. It took 3 tries to recreate the same orientation of the car on the icy curve. Finally, I hit the ice and curve just right, negotiated out of the curve and the light went off.I dunno from.., but maybe it will help someone, or perhaps someone smarter than me knows why and what happened.